#include<bits/stdc++.h>
#define int long long
#define all(v) v.begin(), v.end()
#define SZ(x) (int)x.size()
#define pii pair<int, int>
#define X first
#define Y second
using namespace std;
const int maxn = 2e5 + 10;
const int mod = 1e9 + 7;// 998244353;
const int llmx = 1e18;
struct BIT{
int n;
vector< int > tree;
BIT(int N){
n = N;
tree.resize(n + 1);
}
void modify(int id, int val){
for(; id <= n; id += id & -id) tree[id] += val;
}
int query(int id){
int ret = 0;
for(; id; id -= id & -id) ret += tree[id];
return ret;
}
int query(int l, int r){
return query(r) - query(l - 1);
}
};
void sol(){
int n; cin >> n;
vector< int > v(n + 2), dp(n + 2, llmx), p(n + 2);
for(int i = 1; i <= n; ++i){
cin >> v[i];
p[v[i]] = i;
}
dp[0] = 0;
for(int i = 1; i <= n; ++i){
BIT bit(n + 1), bit2(n + 1);
for(int t = n; t > i; --t) bit.modify(p[t], 1);
int cost = 0;
for(int j = i - 1; j >= 0; --j){
// cerr << i << " " << j << " " << cost << "!!\n";
cost += bit.query(p[j + 1]) + bit2.query(p[j + 1], n);
dp[i] = min(dp[i], dp[j] + cost);
bit2.modify(p[j + 1], 1);
}
}
cout << dp[n] << "\n";
}
/*
5
3 5 2 4 1
// 3
5
3 2 1 5 4
// 0
9
6 1 3 4 9 5 7 8 2
// 9
*/
signed main(){
ios::sync_with_stdio(0), cin.tie(0), cerr.tie(0);
int t = 1; //cin >> t;
while(t--) sol();
}
